A passive restraint belt system automatically transfers a shoulder belt, a lap belt, or both, from a restraining position to a releasing position and vice versa in response to the opening or closing of the vehicle door and makes it easier for a passenger to get into and out of the vehicle. Installation of passive restraint systems will soon become legally obligatory, and several types have already been proposed and studied.
The inventor of the present invention has made extensive studies and put forward several proposals for passive restraint systems, such as a transfer mechanism for the shoulder belt, the lap belt, or both (U.S. patent appln. Ser. No. 950,020, filed Oct. 10, 1978). From the points of view of reliability, practicality, cost of production and so forth, however, there is room for further improvement to arrive at a system for commercialization that will fulfill all requirements. Therefore, further development is continuing.